A surprising share of signup emails are just typos: gmial.com, hotmial.com, yaho.com. Those users never get your welcome email, and they quietly churn. One API call at signup fixes most of it.

Request 

const r = await fetch( "https://webkit-email-validator-link-preview-article-extractor.p.rapidapi.com/email/validate?email=jane@gmial.com", { headers: { "X-RapidAPI-Key": KEY, "X-RapidAPI-Host": "webkit-email-validator-link-preview-article-extractor.p.rapidapi.com" } }); 
{"email": "jane@gmial.com", "verdict": "risky", "score": 70, "did_you_mean": "jane@gmail.com", "checks": {"syntax": true, "mx_found": true, "disposable": false, "role_account": false, "free_provider": false}}

Show "Did you mean jane@gmail.com?" under the field and you've rescued a user.

What it checks

  • Syntax and MX records (can the domain actually receive mail?)
  • Disposable/burner domains for trial-abuse filtering
  • Role accounts like info@ and admin@ for B2B lead scoring
  • Typo suggestions for the big providers

Same API, two more tools

  • /url/preview returns the title, description, image and favicon for link cards (chat apps, CMSs).
  • /url/extract returns the clean article text from a URL, which is handy for summarisers and RAG.

Free tier: 200 calls/month. WebKit on RapidAPI